The invention herein broadly involves yarn carriers, normally tubes, cones, and the like. More particularly, the invention is concerned with yarn pick-up, that is the procedure whereby feeding yarn is directed to and engaged by a carrier or winding tube rotating at high speed for attachment and retention of the yarn to initiate wrapping of the yarn about the carrier.
Many proposals have been put forth for engaging the leading or free end of yarn, some of which require a stationary carrier, and others of which provide for engagement of running yarn with a rotating carrier. For example, it has been known to anchor the free end of the yarn with small bits of glue, adhesive tape, mechanical tabs, clips, and the like. However, the most effective means to date for the securement of running yarn has been the use of pick-up or string-up grooves cut into the periphery of the carrier tubes, normally adjacent one end thereof. Some examples of such pick-up grooves will be noted in the following U.S. Pat. Nos.:
Hartley, Jr.: 3,326,494 PA0 Atwood et al: 3,451,639 PA0 Anderson: 3,625,451 PA0 Adams et al: 3,717,291
Basically, the groove provides a means for rapidly engaging and securing the yarn as the first few wraps are wound about the tube.
While pick-up grooves are substantially universally used, are the subject of a substantial number of patents, and the subject of much research in an effort to improve the performance thereof, such grooves do give rise to basic problems. For example, the presence of the groove within the tube wall, regardless of the configuration thereof, inherently weakens the tube. A further drawback of the use of pick-up grooves is the necessity for providing and maintaining the equipment required to cut the grooves, as well as the labor and time expenditures associated with the additional and relatively exacting steps required to cut the grooves.
Other difficulties inherent in the use of the pick-up grooves include problems associated with a proper engagement of the yarn within the groove, as well as the possibility of difficulties arising in connection with yarn removal from a wedge-locked engagement within the groove.
One attempt to avoid the use of tube grooves has involved, in the fiberglass industry, initial adherence of the yarn to the carrier by wetting the yarn and relying on frictional engagement of the yarn with the rotating tube. This of course requires the presence of a wetting medium and the disruptive effect of the wet yarn on the carrier or tube, particularly when the carrier is of conventional composite multi-layer paperboard construction.